Press with ejector ram operated without auxiliary pressure source



April 28, 1942. P. c. PococK Q 2,280,849

'PRESS WITH EJECTOR RAM OPERATED WITHOUT AUX ILIARY PRES SURE SOURCE Filed June 7, 1958 Jul/entw- PAUL C. PoccJC/r M Patented Apr. 28, 1942 PRESS WITH EJECTOR RAM OPERATED WITHOUT AUXILIARY PRESSURE SOURCE Paul C. Pocock, Marion, Ohio, assignor to The Hydraulic Development Corp. 1110., Wilmington, DcL, a corporation of Delaware Application June 1, 1238, Serial No. 212,321

10 Claims.

This invention relates to presses, and in particular, to arrangements for operating auxiliary rams in hydraulic presses.

One object of this invention is to provide a hydraulic press operating circuit having means for operating an auxiliary ram, such as an ejector ram, without the use of an auxiliary pressure source.

Another object is to provide a hydraulic press operating circuit, wherein an auxiliary ram is operated byiluid supplied to the push-back cylinders which retract the main ram.

Another object is to provide a hydraulic press operating circuit, wherein a single pump is arranged to provide pressure fluid not only for op'- erating the main ram and push-back rams, but also an auxiliary ram, the latter being arranged so that it may be optionally made inoperative,

and so that its speed of operation may be adjusted.

Another object is connected to the push-back rams is an auxiliary ram, such as an ejector ram, wherein the opposite sides of the ram head are of different areas and provide a differential effect according to which the speed of the ejector ram may be adjusted to the desired working conditions. Since ,both sides of the ejector ram are connected to both sides of the push-back rams, this differential effect is regulated by suitable valves placed in the circuit thereof. I

Referring to the drawing in detail, the hydraulic press circuit shown herein comprising a main cylinder l containing the head H of a main plunger l2, the cylinder l0 being surmounted by a surge tank 13. The main plunger I2 is provided with arms l4, connected to the piston rods l5 of the push-back pistons |6, reciprocable within the push-back cylinders H. The main cylinder i0 is provided with ports l8 and |9 at its opposite ends, communicating respectively with conduits and 2| leadin respectively, to the to provide a hydraulic press operating circuit, wherein an independent presfour-way valve 22 and to the surge tank IS. The

conduit 2| is also connected by the conduit 23 to the discharge side of the four-way valve 22, so that the space beneath the main piston head serves merely for the reception of slippage fluid, and does not provide a double-acting efiect.

Leading from the surge tank |3 is the conduit 24 connected at its opposite end to the pump 25 on the suction side thereof. From the pressure side of the pump 25 the conduit 26 runs to the four-way valve 22. The remaining conduit 21 from the four-way valve 22 leads to the lower port 28 in the left-hand push-back cylinder 11. This is connected to a similar port in the righthand push-back cylinder l1 by the cross conduit 29. The upper ends of the push-back cylinders H are provided with ports 30, interconnected by the cross conduit 3|. From the latter the branch conduit 32 runs to the two-way valve 33, from which the conduit 34 runs to the surge tank l3.

Arranged beneath themain plunger 12 is an ejector cylinder 35, having an ejector piston head 36 and ejector plunger 31 reciprocable therein. The cylinder has ports 38 and 39 at the lower and upper ends thereof. From the lower port 38 the conduit 4|) runs to the cross conduit 3|, interconnecting the upper sides of the push-back cylinders l1. From the upper port 33 in the ejector cylinder 35, however, the conduit 4| runs to the cross conduit 29, beyond which the conduit 43 containing the manual valve 42 runs to selectively interconnect the cross conduits 29 and Fluid displaced from the space beneath the pis- In the operation of the press circuit shown in the figure, to perform a pressing stroke the fourway valve 22 is shifted by means of its operating handle 44, so that the pump 25 discharges pres sure fluid through the line 26 the valve 22, the conduit 20 and the port l8, into the space above the main piston head causing the latter to move downwardly and carrying with it the push back plungers l5 and their piston heads |6.

ton head l3 escapes through the conduits 28 and 21, the valve 22, the conduits 23 and 2| to the surge tank l3. Any fluid which has escaped by slippage past the main piston head II will be forced by this same operation through the conduit 2| to the surge tank l3.

When the pressing operation has proceeded farenough, the handle 44 of the four-way valve 22 is shifted so that pressure from the pump 25 is admitted by way of the conduit 26, the valve 22 and the conduits 21 and 29 to the ports 28 in the push-back cylinders l1, beneath the push-back ent invention the ejector portioning the annular ating dies 45 and 46 attached piston heads IS. The valve 42 is assumed to .be closed and the valve 33 open. Under these circumstances, the push-back pistons l6 will rise, carrying with them the main plunger l2 attached tothe main piston head II. The oil forced out of the space -above the main piston head I I is discharged through the port l6, the conduit 20, the four-way valve 22 and the conduits 23 and 2!, into the surge tank l3.

Meanwhile, the fluid forced out of the space above the push-back piston heads [6 is forced through. the ports 30, into the conduits 3|, 32 and 40. Since the two-way valve 33 is assumed to. be open, this fluid will be discharged directly into the surge tank l3 by way of the conduit 34. In order to perform an the operator closes the two-way valve 33. The fluid forced out of the upper portions of the push-back cylinders I1 is therefore forced from the conduit 35, into the conduit 40, and through the port Bit of the ejector cylinder 35, into the space beneath the ejector piston head 36. This action causes the ejector plunger 31 to rise, thereby ejecting the workpiece from the dies, or other holding arrangement.

It will be observed that the return side of the ejector piston head 36 is connected through the conduits 4| and 23 to the lower ends of the pushback cylinders l1. Consequently, a 'difl'erential eflect is produced upon the push-back plungers i5, whereby the difference in area between the bottom of each push-back piston head l6 and the annular space above it provides the unbalanced force which moves the push-back plunger l upwardly. When the ejector has been raised to a sufficient height to eject the workpiece, the operator opens the two-way valve 33. When this occurs the pressure in the space above the ejector piston head 36 will return the latter to its lowermost or retracted position, because the space beneath the ejector piston head 36 is connected, through the conduits 40, 3|, 32 and 34, and the valve 33 to the surge tank 13.

In the usual pressing procedure it is found desirable to eject the workpiece as slowly as possible without stopping or interrupting the press operating cycle. By the arrangement of the presplunger 31 may be made desired by properly proarea above the ejector piston head 36 to the circular area beneath it. Ordinarily, the ejector possesses approximately one-half the stroke of the main ram, hence, a

to operate as slowly as satisfactory design would be to make the ejector plunger 31 move at half the speed of the main ram. This would be done by properly apportionwould cause the ejector plunger 31 and the main plunger l2 to complete their strokes at the same time.

It will be understood by anyone skilled in the press art that many difierent kinds of dies can be employed in connection with the present invention, depending upon the nature of the workpiece to be made. Such dies are well known and their details form no part of the present invention. Merely for purposes of illustration, however, the applicant has shown a pair of cooperto the platen l2 and press bed 50, respectively. When these dies come together they convert the disc-shaped blank 38" into the cup-shaped workpiece indicated by the dotted lines 48*. The die 46 is provided with a bore 49 for the passage of the ej ejection stroke, however,

plunger tor plunger being tor rod 31*. The latter forms an extension of the ejector plunger 31 and ejects the workpiece come within the scope of the claims and the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a hydraulic press circuit, a main plunger, 9. push-back plunger operatively connected with said main plunger and adapted to effect the re-- traction stroke thereof, an ejector plunger operable during the retraction stroke of the main by fluid expelled by said push-back plunger, 2, source of pressure fluid, means for selectively directing pressure fluid from said source to said main plunger or said push-back plunger, and a hydraulic circuit interconnecting said plungers.

2. In a hydraulic press circuit,'a main plunger, 8. double acting push-back plunger operatively connected with said main plunger and adapted to effect the return stroke thereof, a double-acting ejector plunger having fluid connections with both'sides of said push-back plunger and being operable by fluid acted upon by saidpush-back plunger during the working stroke thereof, a fluid reservoir adapted to communicate with one side of said push-back plunger and said ejector plunger, 9. source of pressure fluid forsupplying 3. In a hydraulic press circuit, a main plunger,

a push-back plunger, an ejector plunger, a fluid reservoir, a source of pressure fluid, means for selectively directing pressure fluid from said push-back plunger and said ejector plunger be ing double-acting, the retraction side of said ejechydraulically connected to the push-back side of said push-back plunger and 3 ing the annular and circular areas of the piston head 36 in the manner described above, and

the ejection side of said ejector plunger being hydraulically connected to the return side of said retraction plunger and to said fluid reservoir.

4. In a hydraulic press circuit, a main plunger, a double acting push-back plunger connected with said main plunger, a double acting ejector plunger, a source of pressure fluid, means for selectively directing pressure fluid from said source to one side of said main plunger or said fluid reservoir adapted to communicate with the other side of said main cylinder, and a hydraulic circuit interconnecting said plungers for feeding fluid acted upon by said push-back plunger to said ejector plunger for operatingthe same, the retraction side of said ejector plunger being hydraulically connected to the push-back side of said push-back plunger and the ejection side of said ejector plunger being hydraulically connected to the return side of said retraction plunger.

5. In a hydraulic press circuit,a main plunger, a double acting push-back plunger, a double acting e ector plunger, a fluid reservoir adapted to communicate with one side of' said push-back plunger and said ejector plunger, a source of pressure fluid to said main plunger or said pushback plunger, a hydraulic circuit interconnecting said plungers, the retraction side of said ejector plunger being hydraulically connected to the push-back side of said push-back plunger and the ejection side of said ejector plunger being hydraulically connected to the return side of said push-back plunger, and means for selectively interconnecting the opposite sides of said pushback plungers. 6. In a hydraulic press circuit, a main cylinde with a main plunger, a push-back cylinder with a push-back plunger, an ejector cylinder with an ejector plunger, a fluid reservoir adapted to communicate with said cylinders, a pump, means for delivering the pressure fluid from said pump to the push-back side of said push-back plunger, and means respectively connecting the ejection and return sides of said ejector plunger with the return and push-back sides of said push-back plungers for transferring fluid from said pushback cylinder to said ejector cylinder to operate said ejector plunger.

7. In a hydraulic press circuit, a main cylinder with a main plunger, a push-back cylinder with a push-back p unger, an ejector cylinder with an ejector plunger, a fluid reservoir adapted to communicate with said cylinders, a pump, means for delivering the pressure fluid from said pump to the push-back side of said push-back plunger, meansrespectively connecting the ejection and return sides-of said ejector plunger with the return and push-back sides of said pushback plungers, and meansv selectively connecting said ejector cylinder with said fluid reservoir.

8. In a hydraulic press circuit, a main cylinder with a main plunger, a push-back cylinder with a push-back plunger, an ejector cylinder with an ejector plunger, a fluid reservoir adapted to communicate with said cylinders, a pump, means for delivering the pressure fluid from said pump to the push-back side of said push-back plunger, means respectively connecting the ejection and return sides of said ejector plunger with the return and push-back sides of said push-backplunger, and means selectively connecting the ejection side of said ejector plunger with said fluid reservoir.

9. In a hydraulic press circuit, a main cylinder with a main plunger, a plurality of push-backcylinders, each with a push-back plunger, an ejector cylinder with an ejector plunger, a fluid reservoir adapted to communicate with said cylinders, a pump, means for delivering the pressure fluid from said pump to the push-back side of said push-back plunger, means respectively connecting the ejection and return sides of said ejector plunger with the return and push-back sides ofsaid push-back plungers, and means for selectively interconnecting the push-back and return sides of said push-back plungers.

10. In a hydraulic press circuit, a main 'cylinder witl'ra main plunger, a push-back' cylinder with a push-back plunger, an ejector cylinder with an ejector plunger, a fluid reservoir adapted to communicate with said cylinders, a pump, means for delivering the pressure fluid from said pump to the push-back side of said push-back plunger, means respectively connecting the ejection and return sides of said ejector plunger with the return and push-back sides of said push-back plunger, means selectively connecting the ejection side of said ejector plunger with said fluid reservoir, and means for selectively interconnecting the push-back and return sides of said pushback plunger.

RAUL C. POCOCK. 

